- added native INTERVAL type to the dialect. This supports

  only the DAY TO SECOND interval type so far due to lack
  of support in cx_oracle for YEAR TO MONTH. [ticket:1467]
- The Interval type includes a "native" flag which controls
  if native INTERVAL types (postgresql + oracle) are selected
  if available, or not.  "day_precision" and "second_precision"
  arguments are also added which propagate as appropriately
  to these native types. Related to [ticket:1467].
- DefaultDialect.type_descriptor moves back to being per-dialect.
  TypeEngine/TypeDecorator key type impls to the dialect class
  + server_version_info so that the colspecs dict can be modified
  per-dialect based on server version.
- Fixed TypeDecorator's incorrect usage of _impl_dict

4 files changed, 62 insertions, 5 deletions

diff --git a/lib/sqlalchemy/dialects/oracle/__init__.py b/lib/sqlalchemy/dialects/oracle/__init__.py
index 7b4d6aeab..eb47e80cb 100644
--- a/lib/sqlalchemy/dialects/oracle/__init__.py
+++ b/lib/sqlalchemy/dialects/oracle/__init__.py
@@ -5,11 +5,11 @@ base.dialect = cx_oracle.dialect
 from sqlalchemy.dialects.oracle.base import \
     VARCHAR, NVARCHAR, CHAR, DATE, DATETIME, NUMBER,\
     BLOB, BFILE, CLOB, NCLOB, TIMESTAMP, RAW,\
-    FLOAT, DOUBLE_PRECISION, LONG, dialect
+    FLOAT, DOUBLE_PRECISION, LONG, dialect, INTERVAL
 
 
 __all__ = (
 'VARCHAR', 'NVARCHAR', 'CHAR', 'DATE', 'DATETIME', 'NUMBER',
 'BLOB', 'BFILE', 'CLOB', 'NCLOB', 'TIMESTAMP', 'RAW',
-'FLOAT', 'DOUBLE_PRECISION', 'LONG', 'dialect'
+'FLOAT', 'DOUBLE_PRECISION', 'LONG', 'dialect', 'INTERVAL'
 )
diff --git a/lib/sqlalchemy/dialects/oracle/base.py b/lib/sqlalchemy/dialects/oracle/base.py
index b63953959..882505a40 100644
--- a/lib/sqlalchemy/dialects/oracle/base.py
+++ b/lib/sqlalchemy/dialects/oracle/base.py
@@ -162,6 +162,40 @@ class BFILE(sqltypes.Binary):
 
 class LONG(sqltypes.Text):
     __visit_name__ = 'LONG'
+
+class INTERVAL(sqltypes.TypeEngine):
+    __visit_name__ = 'INTERVAL'
+    
+    def __init__(self, 
+                    day_precision=None, 
+                    second_precision=None):
+        """Construct an INTERVAL.
+        
+        Note that only DAY TO SECOND intervals are currently supported.
+        This is due to a lack of support for YEAR TO MONTH intervals
+        within available DBAPIs (cx_oracle and zxjdbc).
+        
+        :param day_precision: the day precision value.  this is the number of digits
+        to store for the day field.  Defaults to "2"
+        :param second_precision: the second precision value.  this is the number of digits
+        to store for the fractional seconds field.  Defaults to "6".
+        
+        """
+        self.day_precision = day_precision
+        self.second_precision = second_precision
+    
+    @classmethod
+    def _adapt_from_generic_interval(cls, interval):
+        return INTERVAL(day_precision=interval.day_precision,
+                        second_precision=interval.second_precision)
+        
+    def adapt(self, impltype):
+        return impltype(day_precision=self.day_precision, 
+                        second_precision=self.second_precision)
+
+    @property
+    def _type_affinity(self):
+        return sqltypes.Interval
     
 class _OracleBoolean(sqltypes.Boolean):
     def get_dbapi_type(self, dbapi):
@@ -169,6 +203,7 @@ class _OracleBoolean(sqltypes.Boolean):
 
 colspecs = {
     sqltypes.Boolean : _OracleBoolean,
+    sqltypes.Interval : INTERVAL,
 }
 
 ischema_names = {
@@ -204,7 +239,17 @@ class OracleTypeCompiler(compiler.GenericTypeCompiler):
         
     def visit_unicode(self, type_):
         return self.visit_NVARCHAR(type_)
- 
+    
+    def visit_INTERVAL(self, type_):
+        return "INTERVAL DAY%s TO SECOND%s" % (
+            type_.day_precision is not None and 
+                "(%d)" % type_.day_precision or
+                "",
+            type_.second_precision is not None and 
+                "(%d)" % type_.second_precision or
+                "",
+        )
+            
     def visit_DOUBLE_PRECISION(self, type_):
         return self._generate_numeric(type_, "DOUBLE PRECISION")
         
@@ -512,6 +557,10 @@ class OracleDialect(default.DefaultDialect):
         self.implicit_returning = self.server_version_info > (10, ) and \
                                         self.__dict__.get('implicit_returning', True)
 
+        if self.server_version_info < (9,):
+            self.colspecs = self.colspecs.copy()
+            self.colspecs.pop(sqltypes.Interval)
+
     def do_release_savepoint(self, connection, name):
         # Oracle does not support RELEASE SAVEPOINT
         pass
diff --git a/lib/sqlalchemy/dialects/oracle/cx_oracle.py b/lib/sqlalchemy/dialects/oracle/cx_oracle.py
index 5a94efccb..6b1d7e5b9 100644
--- a/lib/sqlalchemy/dialects/oracle/cx_oracle.py
+++ b/lib/sqlalchemy/dialects/oracle/cx_oracle.py
@@ -167,15 +167,19 @@ class _OracleBinary(_LOBMixin, sqltypes.Binary):
     def bind_processor(self, dialect):
         return None
 
-
+class _OracleInterval(oracle.INTERVAL):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.INTERVAL
+    
 class _OracleRaw(oracle.RAW):
     pass
 
-
 colspecs = {
     sqltypes.Date : _OracleDate,
     sqltypes.Binary : _OracleBinary,
     sqltypes.Boolean : oracle._OracleBoolean,
+    sqltypes.Interval : _OracleInterval,
+    oracle.INTERVAL : _OracleInterval,
     sqltypes.Text : _OracleText,
     sqltypes.UnicodeText : _OracleUnicodeText,
     sqltypes.CHAR : _OracleChar,
diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index 308e23bae..2c8f896e9 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -109,6 +109,10 @@ class INTERVAL(sqltypes.TypeEngine):
     def adapt(self, impltype):
         return impltype(self.precision)
 
+    @classmethod
+    def _adapt_from_generic_interval(cls, interval):
+        return INTERVAL(precision=interval.second_precision)
+
     @property
     def _type_affinity(self):
         return sqltypes.Interval